The Doctor would be the first to admit that there were any number of things he didn’t understand about Jack Harkness, the most obvious of them being his propensity for “saying hello” to every sentient being capable of consent that crossed his path. But that wasn’t what really baffled him about Jack.
No, what really baffled him was that no matter where they met, no matter which face he wore, Jack was still in love with him. Every. Single. Time.
“I imprinted on you,” Jack told him over drinks in a rather seedy spaceport bar. He had to stop meeting Jack in places like this, the Doctor thought. It never ended well. (Well. Sometimes it did. For a certain definition of well.)
“Imprinted on me?” the Doctor said, frowning in confusion. “Like a baby bird?”
“Something like that,” Jack said. “You were my first, Doc.”
The Doctor’s eyebrows shot up. “I find that hard to believe.”
Jack laughed. “Not that first, not by a long shot. But you were the first person I fell in love with. The first person I’d loved, period, in a very long time. I wanted you, sure - you and Rose both - but if that were all it was, I wouldn’t still want you two regenerations and four hundred years later.”
“I see,” the Doctor said, slowly, though he wasn’t entirely sure that he did. Love, he understood; he’d loved all his companions in one way or another. But Jack’s love for him was so deep and abiding, it unnerved him. He hadn’t done a thing to deserve it. Quite the opposite, in fact.
Maybe it was a human thing, he thought. Time Lord bonds had tended to be more temporary - at least, more temporary in the context of their very long lives. Marriages were often political and usually didn’t last longer than a regeneration or two. Children were a lifelong commitment, but even those bonds tended to weaken once the children came of age. It was not that the Time Lords hadn’t known love, but that they’d been rather, well, pragmatic about it. It was one of the things he’d disliked most about his people, once he’d learned that there were other ways to be, and yet there were parts of his upbringing that he’d found it very difficult to shake.
Humans, though - humans tended to form lifelong bonds that weren’t easily broken by time or distance. That seemed to be true of Jack as well, no matter that his lifespan was already several times longer than that of the average human.
Jack didn’t say anything, just drank his whiskey and let the Doctor stew. He was in a wandering period, he’d told the Doctor when he’d found him, between homes. But someday, perhaps soon, he’d find a place, a person - more than one, if he was lucky - and settle again, for a time.
The Doctor suddenly wanted to be that person, to have the TARDIS be that place. He hadn’t done a thing to deserve Jack’s love, and he didn’t entirely understand it, but he wanted it all the same.
“Well, Doc,” Jack said at last, “your place or mine?”
He asked that every time. Every time since they’d started meeting like this. “Yours,” the Doctor always said, and they would go back to whatever hole in the wall Jack was renting on whatever nameless spaceport or spaceship he was on. It kept it very clean, very simple - for the Doctor, that was. He had no idea how Jack felt about it.
“Mine,” the Doctor said.
Jack’s eyes widened briefly, but he covered his surprise well. “Yours it is, then,” he said, and tossed back the rest of his drink.
The TARDIS was tucked into a little alleyway, far outside the well-trafficked areas of the spaceport. The Doctor snapped his fingers and the doors opened for them both. There was a slight change in her hum as Jack entered, but like the Doctor, the TARDIS had long grown used to Jack.
He gave Jack a moment or two to adjust, to take in the changes the TARDIS had been through since the last time he’d seen her. But when he turned around, he was surprised to find that Jack was right behind him. The Doctor managed not to startle, not even when, without ceremony, Jack kissed him. The Doctor froze briefly and then kissed him back, simultaneously pulling on his braces to tug him up the stairs where a bedroom awaited them. Not the Doctor’s bedroom, and not Jack’s old bedroom; he wasn’t ready for the former, and he wasn’t sure Jack would ever be ready for the latter. But a bedroom with a big, soft, perfectly serviceable bed.
Sex with Jack was always pleasure tinged with pain. Jack was a Fact, there was no getting around it, and that was uncomfortable. He did things to the Doctor’s time sense that were not entirely pleasant, but then again, he did things to the rest of him that were. The Doctor had learned eventually that if he just managed to get past the initial shock, even the irritation of his time sense assimilated itself into the general hum of his body. With sufficient time and exposure, he wondered if the irritation itself might not become arousing. People certainly had stranger kinks.
Afterward, when they lay together, the irritation returned. The Doctor had always taken the opportunity to leave then; he’d never stayed the night, never tried to fall asleep next to Jack. But now he drew a deep breath and forced himself to relax into the warmth of Jack’s arms. Jack, like all humans, was a furnace compared to the Doctor himself.
“Thank you,” Jack murmured. The Doctor made a questioning noise. “For this, for inviting me in. I’d hoped - but I didn’t want to ask for more than you wanted to give.”
Jack’s hand rested on the Doctor’s stomach. The Doctor covered it with his own and didn’t say anything. Perhaps, he thought, humans knew something he didn’t. Perhaps Jack knew something he didn’t. Love like Jack’s was something you ran toward, not from. It was a love born of a short life, a life that demanded intensity, but perhaps it was possible even for those like himself, like Jack, to have it, too. Jack certainly seemed to think so. The Doctor thought it might be time to try.
In the darkness of the room, surrounded by Jack’s strength and Jack’s warmth and Jack’s Factness, he said the word he knew Jack had been waiting for, patiently, all these many years: